An Interurban, also called a radial railway in parts of Canada, was a type of passenger railroad that enjoyed widespread popularity at the turn of the twentieth century in North America. Interurbans were often extensions of streetcar lines running between urban areas or from urban to rural areas. The lines were mainly electrified in an era when steam railroads had not yet adopted electricity to any large degree. Most could not survive following the widespread adoption of the automobile Those that remained survived as commuter railroads or as freight short lines.
With the demise of the interurban, many routes were taken over by intercity bus services. Most local intercity services have since been discontinued; buses now typically run express between cities. A few interurbans, built to rather high standards, have survived, as have several that still operate only freight service, but the vast majority are long abandoned. Probably the closest present day trolley line resembling a 1920's interurban with city to countryside to small town, side of road, hill and dale operation is the present day broad gauge Upper Darby to Media 100 year old former Red Arrow line of Philadelphia's SEPTA system. The last third of the Media line becomes single track private right-of-way with sidings. The cars move rapidly with a few "flag" stops into and out of wooded ravines, over bridges, and along creek beds to emerge into Media Borough where it runs down the center of Media's main commercial street, State Street. In the early 1900s, this was the Philadelphia and Westchester. It operated all wood arch window heavy interurban cars typical of equipment used nation wide at the time.
The definition of "interurban" is necessarily blurry. Some streetcar systems evolved partly into interurban systems with extensions or acquisitions, while other interurban lines became, effectively, light rail systems with no street running whatsoever, or became primarily freight-hauling railroads with a progressive loss of passenger service.
Another distinction is made between "interurban" and "suburban". A suburban system is oriented toward a particular city center in a single urban area, serving primarily commuters who live in the suburbs of a city. An interurban is more like a regular railroad local train service, moving people from one city center to another with no single center. However, unlike a local train, the interurban serves a smaller region and has more frequent service, and is oriented to passenger rather than freight service, although some small-load freight service was common, especially in the days before trucks (lorries).
In general, interurbans operated with technology somewhere between that of a streetcar line and a full-scale railroad. The vast majority of interurbans were electrified, utilizing simply strung overhead wire, or, on heavily trafficked high speed lines, the more complicated wiring system known as catenary. In either case, power was transferred from the wire to the locomotive (in the case of an interurban freight line) or interurban passenger car by way of a trolley pole or pantograph. Many interurbans transferred electricity to the trains by way of a third rail running parallel to, and outside of, the rails when running on private right-of-way while overhead supply was used elsewhere, notably in built up areas (i.e. Sacramento Northern Railway, and Chicago, Aurora and Elgin Railroad). Power was transferred to the train using a "shoe" attached to the locomotive or car. Engineers working for Michigan United Railways devised a shoe with steel cutters which could remove ice from the tracks.
The interurbans also had to develop their own powerhouses for electricity as there were few commercial power companies in existence at the time. Some of these steam driven power generation houses produced high-voltage AC power that would be stepped-down and converted to DC at the substations using what was called a "rotary converter." The rotary converter was an AC motor driving a DC generator. Because of owning a power house, many interurban railway companies became electric companies to their local regions.
Most power was distributed to the cars using overhead trolley wires or pantographs. Some companies preferred outside third rail. Third rail was cheaper to maintain and improved conductivity, but it was more expensive to construct as it did not mitigate the construction of transmission lines and poles. Third rail was also more dangerous to trespassers and animals. Also, in the winter, third rails were difficult to keep clear of ice.
In 1904, a single-phase alternating current system became available and was distributed by Westinghouse and General Electric. But the system soon proved expensive to maintain and operate, and it increased wear and tear on equipment and track. It was a short-lived experiment and none were installed after 1910.
Another experiment in electrification came in 1907 with high-voltage DC (1200 volts). This system was allowed for easy conversion from other DC systems and was cheaper to maintain. But it was developed so late that few railways adopted it.
In the late 1890s, electrified systems called streetcars, which had been developed by Frank Sprague, expanded rapidly. By 1900, just over of track had been laid, and by 1916, at their peak, over were in service. Most of the interurban track that had been laid was located in Ohio and Indiana; both states had of track. In Michigan and Illinois there was another of track which was interconnected. In Texas and in California, thousands of miles of additional track was also laid down by different companies. The first Interurban in Texas was the Denison and Sherman Railway, completed in 1901. In central Virginia, interurban lines connected City Point and Hopewell with Petersburg, and Petersburg with Richmond. Another connected Richmond with Ashland.
In the early 1900s, interurban transportation was very popular in both rural areas and cities. Although slower in speed than steam driven passenger trains, the interurban system made up for speed by increased frequency of service. After 1910, the popularity of the Ford Model T automobile began to diminish the interurban passenger load, and during the 1920s, many interurban systems were declared bankrupt. Many were also bought out in the Great American Streetcar Scandal and deliberately destroyed. As a result of this shift in transportation methods, the small and unprofitable lines were discontinued. By the 1930s, most of the interurbans had disappear, although some of their rail lines were taken over for the use of freight drawn by steam engines. Most were replaced with buses. By the 1960s, very few lines remained; the Pacific Electric Railway in California was abandoned in 1961, and the Chicago North Shore and Milwaukee Railroad near Chicago in 1963.
Few historic interurban lines are still operated in their original form, although a number of more recently-constructed transit lines could be considered interurbans by Hilton and Due's standards above.
Other lines that have some characteristics of an interurban include:
Other portions of interurbans remain in service as parts of regular freight-hauling railroads; for instance, portions of the Sacramento Northern Railway were operated by the Union Pacific Railroad. The longest surviving portion of the Sacramento Northern is now owned by the Sierra Northern Railroad. Most of the Tidewater Southern Railway is still operated by the Union Pacific. Another California interurban company, the Central California Traction Company, still operates diesel freight service on its one-time electric line between Stockton and Lodi.
In Southern Ontario, intercity streetcar lines were called radial railways, because their routes generally radiated from a central city. The longest routes from Toronto included one running to Lake Simcoe and another to Guelph. A portion of one of these lines is preserved and plays host to a working museum of streetcars and other transit vehicles at the Halton County Radial Railway in Milton. A notable feature of Toronto's radial railways was that because the city streetcar tracks of the Toronto Railway Company (later taken over by the Toronto Transportation Commission) were built to a wider gauge (which is still used to this day), radial cars from the outlying areas could not pass the city limits, requiring passengers to change trains.
Some of the closer sections of Toronto's radial railways were assimilated into the city's streetcar network, and with the city's expansion, some communities once linked by radial railway now have relatively central stations on the Toronto subway. On a regional level, GO Transit's commuter railway network is designed on a similar radial principle, though it uses much heavier-capacity mainline trains.
There were also significant radial systems operating from Hamilton, St. Catharines, Windsor, and throughout the Grand River Valley, the last of which may see a revival should Grand River Transit obtain funding to build a light railway between Waterloo, Kitchener, and eventually Cambridge, running partially on the tracks of the former Grand River Railway. Hamilton and the Niagara Region are also investigating the possibility of reviving former interurban railway routes as modern light rail.
In British Columbia, five interurban lines were operated by the British Columbia Electric Railway Company. The private right-of-way of the Central Park line, between Commercial Drive in Vancouver and New Westminster, is now used by the SkyTrain's Expo Line. The Fraser Valley Line became the British Columbia Hydro Railway when BC Electric was nationalized in the 1960s; it was later privatized and is now the Southern Railway of British Columbia, a local shortline freight railway. The BCER also operated interuban trains between Vancouver and Marpole, and between Marpole, Steveston and New Westminster on the Vancouver and Lulu Island Railway, which it leased from Canadian Pacific. This railway is also known as Arbutus Corridor route. Likewise, the Millennium Line of the SkyTrain connects the same communities as the former Burnaby Lake Line; however, the new SkyTrain line does not follow the original right-of-way, which is now the route of Highway 1 through Burnaby. The fifth BCER interurban connected Victoria and Patricia Bay on the Saanich Peninsula. Its right-of-way is commemorated by Interurban Road in Saanich.
In Nova Scotia, the Cape Breton Electric RCompany operated interurban services between Sydney, Glace Bay and New Waterford from 1901 to 1947, and the Pictou County Electric Company operated interurban services between the five towns of Pictou County from 1904 to 1931.
The Netherlands used to have an extensive "tram-system" that came very close to the American-style interurban. The standard gauge NZH trams in the area between The Hague, Leiden and Haarlem were fairly big electric trams running on 1200 volt with in-street running in towns and quite a lot of private right-of-way outside towns. Especially the "Budapester" trams (see picture) resembled American interurban cars. A typical tram was made up by coupling a motorised unit (A400 or A500 series) with one or two trailors (B400/B500). In common with American practice the NZH also had local streetcar lines in The Hague, Leiden and Haarlem sharing some of the track with the interurban routes. Power supply was entirely by overhead wire. Although there was a connection between tram and train tracks in Leiden it was not possible to convey railway cars on NZH track due to differing track and wheel geometry, curve radius and loading gauge. The A/B600 series of twin-cars, built around 1930, resembles those of Oaklands Key System 'Bridge Units' built slightly later.
Part of the NZH system was built to metre-gauge. In the nineteentwenties the same "Budapester" interurbans were bought for use here (with narrower wheel-sets of course). It was envisioned that some of this track would be converted to standard gauge at a later date but the axe fell before this could occur. Because the terminus of one of these lines was in the centre of Amsterdam (where the streetcars use standard gauge) some three-rail track (combined standard/narrow gauge) existed there. Long after the demise of the NZH-interurbans the tree-rail track was still present in some streets with interesting pointwork where streets crossed.
Nowadays few lines remain, one of which is Line 1 of HTM, running from Scheveningen to Delft. NZH turned into a bus company and in 1999 was taken over by Connexxion. However Connexxion also runs the light-rail line from Utrecht to Nieuwegein that was built around 1980 but has roots in the steam-tram era. In addition, until 2006 Nederlandse Spoorwegen ran two regional lines between The Hague and Rotterdam Hofplein/Zoetemeer as a train (heavy-rail) service, and these were then changed into Randstadrail, a concept similar to the old interurbans. Interestingly this "Hofplein-line" started early 20th century as a separate company (ZHESM) modelled after the American style interurbans (running fully electric multiple-unit trains right from the start) but was included into the nationalised rail system later on.
One of these cases are the many early sondary (connecting) railway lines that were built in the onset of the 20th century. Many of them were street-running in urban and suburban areas while using a dedicated right of way in less populated areas. Those lines were usually operated with mainline stock, however very few were electrified. Most of them have disappeared or were moved onto a fully dedicated right of way due to increasing street traffic and safety concerns. One of the few such railway lines still in service is the steam operated narrow-gauge Molli train between Bad Doberan and Kühlungsborn West on the shore of the Baltic Sea in the north-eastern state of Mecklenburg-Vorpommern which is street-running inside Bad Doberan and has its own right of way on the rest of the line.
Another not uncommon case are interurban tramways. Germany has numerous areas where several larger cities are clustered together, and there were always places not served by mainline railway lines. Often urban tramways companies jumped at the opportunity and built over-land tramway lines, sometimes linking two existing tramway networks together. Those lines were run with standard tramway cars.
After World War II these Interurban tramways were modernised and now dubbed Stadtbahn. All of them are street-running in city areas and use a dedicated right of way between cities, and all of them are electrified. Rolling stock used is either standard tramway cars or special heavier cars which still qualify for tramway use in street-running lines as regulated in BOStrab. Generally, the stadtbahn systems fit the definition of an interurban once their network leaves city boundaries.
One particularily large effort was the Stadtbahn Rhein-Ruhr which was meant to grow to a length of 300 km (180 miles), spanning over 10 cities of the Ruhrgebiet industial area, building upon already existing interurban and urban tramway lines. Although those plans were later abandoned due to exploding costs, 17 Stadtbahn lines between Krefeld in the west and Dortmund in the east were finished and today one can travel from Krefeld to Bochum without using a single mainline train. The only link missing is between Bochum and Dortmund.
In Kansai region mostly from Osaka
In other regions